Smash may not appeal to someone who doesn’t already like musical theater. But to anyone who occasionally finds herself absent-mindedly humming Les Mis’s “Confrontation” – or, okay, shamelessly trying to belt out both parts at once – this glitzy, refreshingly earnest show’s potential is nothing short of thrilling. As long as it doesn’t get bogged down by snore-inducing subplots (ahem, Debra Messing’s baby mama drama) or overly mired in showbiz cliches, Smash has every right to be a… well, you know.

We fade in on a girl with a hunger for fame. Her name is Karen Cartwright, and she’s singing a soaring rendition of “Somewhere Over the Rainbow” on an empty stage. Don’t adjust your television screen if this seems familiar – as endless Smash promos have blared, Karen’s played by American Idol runner-up Katharine McPhee. And yes, she’s performing a tune that became her signature on that reality competition.

Unfortunately, Karen’s audience isn’t quite as taken with the number as Simon Cowell was. The telltale sound of a cell-phone ring interrupts her rhapsody – and we quickly learn that the stage and the swelling orchestra were all in Karen’s head, Chicago-style. She’s actually auditioning for a table of bored-looking theater pros – one of whom has just taken a call in the middle of her song. As Karen will soon tell her devoted boyfriend Dev, “No, it did not go well!” McPhee skeptics: Listen to the way she delivers that line, then tell me she isn’t a good actress.

Once Karen shuffles out of the room, she’s immediately replaced by a bubbly pro: Ivy Lynn, a gal who knows the importance of a confident strut and some killer cleavage. Something tells me Ivy must be very popular on the audition circuit. She’s played by Megan Hilty, a triple-threat dynamo who deserves to be Smash’s true breakout star.

Our next stop on the Character Introduction Train: Tom and Julia, the composer-lyricist team behind fictional Broadway fare like Heaven on Earth and Three on a Match. (Crimean war superstition – great musical theater fodder, right?) Julia favors schlubby-chic scarves and is played by Debra “Grace” Messing; Tom has adorably flopsy hair and is played by Christian Borle, a Tony nominee who also happens to be a graduate of my high school. Pittsburghers are doin’ it for themselves! Tom’s just arrived home from London to find that his new assistant, Ellis, has sorted his mail, organized a “tea drawer” and even made him a giant dish of mac and cheese. Ellis is the best! Actually, Ellis is kind of the worst. But more on that later.

While the boss was away, Assistant Boy also took the liberty of perusing Tom’s coffee-table books – namely, a big, glossy volume about Marilyn Monroe. “Oh, Marilyn – so beautiful, so tragic,” says Julia, who today will be playing the role of Captain Obvious. Ellis says casually that he thinks she’d be a great subject for a musical. At first, Tom and Julia are dubious; Broadway tried the idea once already, and besides, everyone from Michelle Williams to freakin’ Gossip Girl is doing her now. But the more they think about it, the more invested in the idea they become. Especially because Julia has been itching to pen a baseball number filled with sex puns.